It can be time consuming
You can remove and replace one joist at a time
The cost will depend on how many joists need to be replaced. You can just add the new joists and abandon the existing joists in place
If you can't get in from below, you'll need to remove the floor above and replace them all from above, then install floor
Then you won't have to rip up the floor
That will save some money
I would abandon the existing joists in place and just add new joists, it will save labor
I wouldn't expect this to be terribly expensive, but it will depend on the quantity of lumber to be installed and the conditions to get in the space.
Yes, did you get my last messages?
Are you not getting my messages?
The treated lumber is relatively inexpensive. Treated 2x10x12's vary from $12-$16. The labor should be minimal if they have ample work space
If you've found my answer helpful, please "accept" it. I'll be happy to answer additional questions on the topic. If you could provide feedback, I would appreciate it.
I would estimate about $7 - $10 per foot depending on the working conditions, but it will vary with contractors and with the space they have to work
That was why I said you should consider abandoning the existing joists in place and just installing new joists.
Unless there is dry rot or wet rot or termites, I'm having a hard time thinking of a reason that the existing joists need to be removed. You can abandon them in-place and not count on them for anything and just install the new joists in between the existing. This will not require supporting the first floor, which I'm sure is the bulk of the estimate you have.
90' of joist should NOT be costing you $13,500!
Unless the guys are on their stomachs in a 3' crawl space with no lighting and horrible working conditions.
If this was helpful to you, please "accept" so I can be paid for my time. If you don't "accept" then I don't get paid.